Methods and systems for maintaining the temperature of wastewater in a treatment facility

ABSTRACT

Volatile organic compounds (VOCs), such as benzene, toluene, ethylbenzene, xylene and methanol may be removed from wastewater obtained from oil or gas exploration or production operations by way of a bioreactor. The bioreactor may employ anaerobic microorganisms that metabolize various VOCs. In some embodiments, such a bioreactor may be configured to selectively change the temperature of the conditions of wastewater placed in the bioreactor, or of wastewater re-circulated through the bioreactor. A centralized valving or control station may optionally control heating or other conditioning elements for both feed and re-circulation systems.

CROSS-REFERENCE TO RELATED APPLICATIONS

A claim for priority is hereby made pursuant to 35 U.S.C. §119(e) toU.S. Provisional Patent Application No. 61/677,998, filed Jul. 31, 2012,and titled METHODS AND SYSTEMS FOR MAINTAINING THE TEMPERATURE OFWASTEWATER IN A TREATMENT FACILITY (“the '998 Provisional Application”)is hereby made. The entire disclosure of the '998 ProvisionalApplication is expressly incorporated herein by this reference.

TECHNICAL FIELD

This disclosure relates generally to the treatment of wastewater. Morespecifically, this disclosure relates to methods and systems formaintaining favorable environmental conditions for anaerobic digestionof volatile organic compounds (VOCs) within wastewater. Moreparticularly still, this disclosure relates to methods and systems thatmix contents of a bioreactor, or digester and/or which maintain thecontents at a desired temperature that promotes digestion of VOCs.

RELATED ART

Wastewater is a byproduct of many different manufacturing, agricultural,oil and gas exploration and production (E&P), and other industries. Forinstance, a manufacturing facility may use cutting fluid when milling,turning or otherwise forming different mechanical components. Somecutting fluid may be recovered; however, other cutting fluid may bemixed with water making it unsuitable for use as a cutting fluid as wellas for consumption or other use.

Similarly, water is often present with oil or gas in oil and gasreservoirs. Thus, when oil and gas are extracted from a well, water isalso usually present. This is particularly the case as a well isdepleted. As the density of water is greater than that of oil or gas,water tends to be located near the bottom of the well, and more and morenaturally occurring water is then extracted upon depletion of the well.

In E&P processes, water may also be introduced into a well andthereafter removed with oil or gas from the well. Among other purposes,water may be introduced into a well in a process known as “flooding” todisplace oil or gas within the well. Water may be injected into a wellto increase pressure within the well and to thereby stimulate the wellto maximize its production of oil or gas, a technique that is known inthe art as “hydraulic fracturing.” Like naturally occurring water, waterthat has been introduced into a well accompanies oil or gas out of thewell. Depending upon its original source, the water that is removed fromthe ground along with oil or gas is known in the art as “flow-backwater” (for water introduced into and subsequently removed from thewell) or as “produced water” (for water that was already present withinthe well). Water that is removed from an oil or gas well is consideredto be E&P waste.

Whether wastewater is produced in E&P waste, or is part of agricultural,mechanical, or other processes, the wastewater can include any number ofdifferent hazardous air pollutants (HAPs), including volatile organiccompounds (VOCs). Example VOCs include the so-called “BTEX” materials(i.e., benzene, toluene, ethylbenzene and xylene). In addition, incolder environments, methanol (CH₃OH), another HAP, may be used as anantifreeze (e.g., and introduced into a well or used in anotherprocess). The methanol may mix with water and also be present inwastewater.

Various processes have been used to treat wastewater to neutralizeand/or remove HAPs. Conventionally, wastewater has been transported to awater treatment, or remediation, facility. At such a location, phase(i.e., oil and water) separable hydrocarbons and sludge are removed fromthe wastewater before disposing of the wastewater. One of the morecost-efficient methods for disposing of E&P wastewater, for instance,employs evaporation ponds. From an evaporation pond, the E&P wastewatermay be introduced back into the environment (e.g., into the atmosphere,into ground water, etc.), along with a portion of the HAPs originallydissolved in the wastewater. From an environmental perspective, theplacement of E&P wastewater that includes dissolved HAPs intoevaporation ponds is less desirable than other, more expensive disposalmethods.

To enhance the removal of undissolved VOCs, the Environmental ProtectionAgency (EPA) and analogous agencies have implemented environmentalregulations requiring that wastewater be treated before it may be placedinto evaporation ponds. Under such regulations, the wastewater may bepassed through various filters, enhanced gravity separation,emulsification removers, chemical treatment and other advanced treatmentdevices. Some treatments may also include using anaerobic bacteria thatmetabolizes dissolved VOCs and other HAPs, and converts them into othermore products (e.g., carbon dioxide or methane gas) that can be moreeasily removed from the wastewater. The anaerobic bacteria may besensitive to various changes in the environment. For instance, duringwinter months when temperatures decrease, the wastewater naturallycools. When cooled, the anaerobic bacteria operate more slowly, and thusmetabolize less of the VOCs and produce less gas byproduct. Thus, thewastewater has to be treated longer, or is released into evaporationponds despite significant amounts of dissolved VOCs remaining in thetreated water. The wastewater may thus potentially pollute theatmosphere and ground water.

SUMMARY

This disclosure relates to the treatment of E&P wastewater, which isalso referred to herein as “wastewater,” recovered from oil and gasexploration and production sites. In addition to being useful fortreating E&P wastewater, the apparatuses, systems and methods disclosedherein may be used to treat wastewater from other sources (e.g.,manufacturing, agricultural, consumer, commercial, etc.). Morespecifically, apparatuses, systems, facilities and methods for removingdissolved volatile organic compounds (VOCs), which are widely consideredto be hazardous air pollutants (HAPs), from wastewater. The various VOCsthat may be removed from wastewater include, but are not limited to,methanol (i.e., methyl alcohol) and the so-called “BTEX” materials(i.e., benzene, toluene, ethylbenzene and xylene). These materials maybe safely removed from wastewater and converted to less harmfulsubstances (e.g., carbon dioxide (CO₂), water vapor, methane (CH₄),etc.) by anaerobic bacteria or other microorganisms.

In one aspect, a system includes a vessel operating as a bioreactor, ordigester, for treating wastewater. The bioreactor or systems associatedtherewith may provide a favorable environment for anaerobicmicroorganisms. In addition, the bioreactor may include one or moreelements for continually or occasionally re-circulating the contents ofthe bioreactor, including the anaerobic microorganisms and anywastewater within the vessel. The bioreactor vessel may take a varietyof configurations, depending at least in part upon the volume ofwastewater to be treated and the location where the wastewater is to betreated. Where relatively small volumes of wastewater are to be treated(e.g., on the order of hundreds of barrels, 500 barrels or less, etc.),the bioreactor vessel may comprise a tank, such as a frac tank of thetype commonly used in the oil and gas industry. When larger volumes ofwastewater are to be treated, the bioreactor vessel may comprise a pool,pond or other fluid constructed for this purpose at a wastewatertreatment facility.

The anaerobic microorganisms of a bioreactor are selected to metabolize,or digest, various VOCs that have dissolved in the wastewater, includingmethanol and the BTEX materials, while withstanding the harsh conditionsthat are typically present in wastewater from oil and gas exploration orproduction (e.g., the VOCs, other pollutants, etc.) or other processes.The ability of the anaerobic microorganisms to metabolize VOCs may beoptimized and maintained by carefully monitoring and controlling variousconditions within the bioreactor vessel.

In one aspect, this disclosure relates to systems for treatingwastewater. In addition to a bioreactor vessel, such a system includes avariety of other elements, including components for controlling andmaintaining desired conditions within the bioreactor vessel, andcomponents for providing wastewater to the bioreactor vessel. Inaccordance with one illustrative example, a vessel containing untreatedwastewater may provide the untreated wastewater to the bioreactorvessel. A valving station that includes one or more conditioningelements may be used to adjust the conditions of the feed wastewater tomaintain wastewater in the bioreactor vessel at desired conditions.Valves and other elements in the valving station may be used to selectwhich conditioning elements are to be used, although, if desiredconditions are already present, the valves may allow the feed wastewaterto bypass one or more conditioning elements.

An example system for maintaining desired conditions may include one ormore pressure elements (e.g., pumps, gravity feed systems, etc.) forconveying wastewater from the feed vessel to the bioreactor vessel. If acondition (e.g., temperature, etc.) of the wastewater is outside of adesired range (e.g., too high or too low), a valving station that isdownstream from the feed vessel and upstream from the bioreactor vesselmay cause the feed wastewater to be heated, cooled, or otherwiseconditioned so as to obtain conditions that match those of thebioreactor vessel, or can be used to change the conditions in thebioreactor to a desired level. Thus, if the feed water is colder than isoptimal for anaerobic microorganisms to metabolize VOCs, the feed watermay be heated to a desired level. Similarly, if the temperature ofwastewater in a bioreactor is colder than desired, feed water can beheated so as to raise the entire temperature within the bioreactorvessel. The desired temperature can thus be maintained by controllingwhen and to what degree temperature or other conditions of the feedwater are changed.

Another example system may maintain desired conditions through use of are-circulation system connected to, or included within, the bioreactorvessel. An outlet may take wastewater, sludge or other materials fromthe bioreactor vessel, move them, and re-introduce them into thebioreactor vessel (or a portion thereof). The re-circulation may mix theanaerobic microorganisms to redistribute them throughout the wastewater.Such redistribution may allow the anaerobic microorganisms to operatemore efficiently in the breakdown of the wastewater.

Re-circulation may thus be used to maintain desired conditions within abioreactor system. Re-circulation may be controlled using a valvingstation. Using the valving station, one or more types of materials(e.g., wastewater, sludge, anaerobic microorganisms) may be removed andre-circulated to enhance operation. Valves may control which types ofmaterials are removed and how they are mixed together. In accordancewith some aspects, the valving station may use a heating or otherconditioning element to further maintain desired conditions. Ifwastewater in the bioreactor vessel is, for instance, too cold foroptimal performance of the anaerobic microorganisms, valves may beopened or closed as necessary to direct the re-circulated materialsthrough a heater to raise them to a desired level (e.g., the temperatureat which optimal performance is obtained, an above-desired temperatureto mix with the contents of the bioreactor vessel and increase thetemperature within the full vessel to a desired level, etc.). When adesired temperature is present, the valving station may close valves tothe heating element, thereby bypassing the heating element and merelyre-circulating the removed materials.

Some embodiments of the present disclosure contemplate a bioreactorsystem that maintains desired conditions by controlling feeding,re-circulation and heating. Optionally, a central valving station may beused to both feed wastewater to a bioreactor vessel and to re-circulatematerials within the bioreactor vessel. Separate pumps, gravity feedmechanisms, or the like may be used for feeding and re-circulating, orall or some aspects of feeding and re-circulating wastewater may becombined into operation of a pump or other device. A heating element forheating transferred fluid may be used in connection with a set of one ormore valves. Thus, as the temperature of feed or re-circulated water istoo low, the valving station may direct the corresponding wastewater tothe heating element. In contrast, if the temperature is suitable, thevalving station may direct the wastewater to bypass the heating element.Centralized control may be provided by a valving station for any or allaspects related to controlling conditions of a bioreactor system,including feeding, mixing, re-circulating, draining, etc. the bioreactorvessel.

A valving station of some embodiments may be used regardless of whetherthe bioreactor system is a large-scale system including a bioreactorpond fed from a skim pond, or in a smaller-scale, and even portablesystem.

Methods for treating wastewater and maintaining wastewater at a desiredtemperature or other condition are also disclosed. Broadly, such amethod includes isolating wastewater from hydrocarbons and solidmaterials (i.e., sludge) and removing VOCs from the wastewater. Bycontrolling the conditions of the wastewater, dissolved VOCs may bemetabolized by anaerobic bacteria in an optimized manner and removedfrom the wastewater.

In a specific embodiment for treating wastewater and maintaining thewastewater at a desired temperature, untreated wastewater is accessedfrom a feed reservoir. The untreated wastewater is transferred to abioreactor reservoir for mixing with treated wastewater and anaerobicmicroorganisms. The treated and/or untreated wastewater may beconditioned. For instance, when the untreated wastewater is conditioned,the untreated wastewater may be selectively transferred to a heater orother conditioning element after being output from the feed reservoirand prior to being input to the bioreactor reservoir. When the treatedwastewater is being conditioned, the treated wastewater may bere-circulated and selectively transferred to the conditioning elementand thereafter re-input into the bioreactor reservoir. The untreatedwastewater can then be treated with the anaerobic microorganisms toreduce a content of volatile organic compounds dissolved in theuntreated wastewater.

Other aspects, as well as features and advantages of various aspects, ofthe disclosed subject matter will become apparent to those of ordinaryskill in the art through consideration of the ensuing description, theaccompanying drawings and the appended claims

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 schematically illustrates an embodiment of a bioreactor systemfor maintaining desired conditions within wastewater in which VOCs arebeing removed;

FIG. 2 is a cross-sectional view of an embodiment of a large-scalebioreactor system of a wastewater treatment site, the bioreactor systemincluding a valving system for maintaining favorable conditions withintreated wastewater;

FIG. 3 is a schematic representation of a bioreactor system having avalving station between feed and bioreactor reservoirs, the valvingstation including valves and a heating element for selectively heatingfeed wastewater and/or re-circulated wastewater; and

FIG. 4 is a schematic representation of another bioreactor system havinga valving station for selectively heating feed wastewater and/orre-circulated wastewater.

DETAILED DESCRIPTION

According to one aspect of this disclosure, a properly configuredbioreactor may be configured to remove volatile organic compounds (VOCs)and other hazardous air pollutants (HAPs) present in wastewater from thewastewater. The wastewater may originate from any number of sources,including from an oil or gas well in connection with oil exploration andproduction (E&P) systems, from agricultural systems, from domestic orresidential properties, or from other sources or any combination of theforegoing.

In various embodiments, a bioreactor system may include a feed vesseland a reactor vessel. Generally speaking, wastewater may be contained inthe feed vessel may be provided to the reactor vessel where anaerobicmicroorganisms (e.g., anaerobic bacteria) metabolize the organiccompounds in wastewater, including but not limited to VOCs and/or otherHAPs. In the same or other embodiments, the bioreactor system mayinclude a reactant optimization system for maintaining favorableenvironmental conditions within wastewater treated within, or fed to,the reactor vessel. The reactant optimization system may include heatingand/or mixing components which may be used to maintain the wastewater ata favorable temperature and/or distribute anaerobic microorganismsthroughout the wastewater in the bioreactor vessel. A bioreactor systemmay also include an outlet from which produced biogas may be collected.

As shown in FIG. 1, a bioreactor system 100 may include one or morefluid reservoirs 102, 104. The reservoirs 102, 104 may be tanks or othervessels capable of selectively holding a fluid. For simplicity, thefluid reservoirs 102, 104 may each be referred to herein as a “tank”,although the fluid reservoirs 102, 104 are not limited to any particularstructure or form.

According to some embodiments, the tank 102 may be a feed vessel whichstores or otherwise holds wastewater that is fed or otherwise providedto the tank 104. The tank 102 may include an inlet 106 to the interiorthereof, as well as one or more outlets 108. In this particularembodiment, an inlet 106 may allow wastewater 120 or other fluids to beplaced within the interior of the tank 102. The outlet 108 may lead toan exterior of the tank 102. Such an outlet 108 may allow the tank 102to be drained or otherwise allow the wastewater 120 to be expelled fromthe tank 102. In at least some embodiments, the outlet 108 mayfacilitate moving of wastewater 120 from the tank 102 to or towards thetank 104.

The tank 104 may also have wastewater 120 therein. One or more inlets110, 112 may be used to move the wastewater 120 into or through the tank104. In this particular embodiment, the tank 104 includes two inlets110, 112, although any number of inlets may be provided. According tosome embodiments of the present disclosure, wastewater 120 within thetank 102 may be placed within the tank 104 through at least the inlet110.

According to some embodiments of the present disclosure, the tank 104may also be a bioreactor, or digester, which contains anaerobicmicroorganisms 122. The anaerobic microorganisms 122 may comprise one ormore different microorganisms (e.g., bacteria, etc.) that metabolize thevarious VOCs (e.g., the BTEX materials, methanol, etc.) and, optionally,other HAPs that may be present within the wastewater 120. VOCs may beconstantly contained to prevent their introduction into the environmentand, therefore, provided little or no elemental oxygen (O₂) at thesurface of the wastewater 120. Consequently, the microorganisms that areused to metabolize the VOCs may be able to live with little or no oxygen(i.e., they are anaerobic). As different microorganisms may metabolizeone or more types of VOCs, but not all of the different types of VOCsthat are typically present in wastewater 120, the anaerobicmicroorganisms 122 that are used in the bioreactor system 100 mayinclude a mixture of different microorganisms. In a specific embodiment,the anaerobic microorganisms 122 comprise a mixture of microorganismsfrom wastewater treatment sites with sludge having a high totaldissolved solids (TDS) content (e.g., a TDS content of about 1,500 mg/Lor more, a TDS content of about 2,500 mg/L, etc.). In some embodiments,the anaerobic microorganisms 122 may be acclimated to withstand a TDScontent of up to about 20,000 mg/L, up to about 25,000 mg/L, or more.

As the wastewater 120 is in the tank 104, the various components andmaterials may separate. For instance, solid materials (sludge) 124 mayhave a higher density than the liquid wastewater 120, and may fall tothe bottom of the tank 104. The anaerobic microorganisms 122 caninteract with the organic materials within the wastewater 120 and/orsludge 124 to break-down the organic materials. Optionally, theanaerobic microorganisms 122 produce a gas byproduct. An outlet 114 maybe located near a top of the tank 104 to enable the removal of suchgases (e.g., methane, etc.) which are produced during the treatment ofthe wastewater 120 (e.g., the metabolism of VOCs by the anaerobicbacteria 122, etc.) in the tank 104, enabling pressure that buildswithin the tank 104 to be periodically released and potentiallycollected.

In accordance with various embodiments, the wastewater 120 and/or solidmaterials/sludge 124 may be moved or mixed. In such a process, theanaerobic microorganisms 122 may also be moved and redistributedthroughout the wastewater 120. Such redistribution may allow theanaerobic microorganisms 122 to operate more efficiently in thebreakdown of the wastewater 120 and/or the production of the gasbyproduct.

Movement of the wastewater 120, sludge 124, microorganisms 122, or anycombination thereof, may be accomplished in any suitable manner. In someembodiments, for instance, an agitator, mixer, sparger, or other devicemay be positioned within the tank 104 and used to move and mix thecontents within the tank 104. In the same or other embodiments,materials may be moved out of the tank 104 and then re-introduced intothe tank 104. Such movement can create a flow that mixes the materialswithin the tank 104. FIG. 1 illustrates an example of such a system 100,and includes a valving station 128 that can be used to facilitate theflow of materials in and out of the tank 104.

More particularly, the tank 104 of this illustrative example includestwo outlets 116, 118 enabling removal of substances from the interior ofthe tank 104 and their communication to locations outside of the tank104. As illustrated, one of the outlets (i.e., outlet 118 in theillustrated embodiment) may be located near a top of the tank 104 so asto enable clarification of the wastewater 120 (e.g., by gravity, etc.)as the wastewater 120 is removed from the tank 104, leaving some or allof the solid materials 124, sludge and the anaerobic bacteria 122 withinthe interior of the tank 104. Physical structures such as filters,baffles, and the like may also be provided to create a physical barrierbetween portions of the interior of the tank 102 and the outlet 118 toenable clarification of wastewater 120 exiting the interior of the tank104.

An outlet 116 may, in contrast, be positioned at or near a bottom of theinterior of the tank 104, and lower relative to the outlet 118 whichremoves the wastewater 120. Sludge or other solid materials 124 that areleft behind and sink to the bottom of the tank 104 may be removedthrough the outlet 116. Valves, including valves associated with thevalving station 128, may be used to control movement of the solidmaterials 124 through the outlet 116.

Removal of liquids, sludge, or other materials from the tank 104 may beperformed in any suitable manner. For instance, a valve may beassociated with each of the inlets and the outlets of the tanks 102, 104to control the movement of fluids into or out of the tanks 102, 104.Such valves may be located at or near the tanks 102, 104 and/or in otherlocations. As shown in FIG. 1, for instance, the valving station 128 mayinclude one or more pumps 130, 132. Such pumps 130, 132 may be pressureelements that can create suction to remove the wastewater 120,microorganisms 122, solid materials 124, or other materials or anycombination thereof. Valves (not shown) may be used and opened andclosed to determine when a pump 130, 132 draws from a particular tank102, 104.

Examples of valving stations are described in greater detail hereafter,and particularly with respect to FIGS. 3 and 4. The valving station 128may, however, have any suitable configuration and is not limited to thatillustrated or those shown in FIGS. 3 and 4.

As shown in FIG. 1, an example valving station 128 may allow materialsto be removed through the outlets 116, 118, whether by using the pumps130, 132 or other mechanisms. The removed materials may be removed fromthe tank 104, routed through the valving station 128, and back into thetank 104 through one or more inlets 110, 112. Such a configuration mayre-circulate materials as described above. Optionally, the outlets 116,118 may direct materials into a single pump (e.g., pump 130).Alternatively, multiple pumps (e.g., pump 130, 132) may be used for allor portions of the materials removed from the tank 104. Moreover, one orboth of the pumps 130, 132 may also or alternatively be used to assistin moving wastewater or other materials from the tank 102 to the tank104. The valving station 128 may thus assist the tank 102 in acting as afeed tank for providing wastewater to the tank 104 which operates as abioreactor, or digester.

Although the illustrated embodiment shows a valving station 128 with aset of pumps 130, 132, it should be appreciated in view of thedisclosure herein that any suitable manner for moving the materials intoand/or out of the tanks 102, 104 may be used. In other exampleembodiments, for instance, pump may be replaced or supplemented byanother pressure element, including a gravity feed or other alternativesystem, or any combination thereof.

The valving station 128 may also include one or more optionalcomponents. Shown in FIG. 1, for instance, materials output from thepumps 130, 132 may pass through an additional component 134. Theadditional component can take any suitable form. By way of illustration,the component 134 may include a heating element configured to heat fluidentering the tank 104 from the tank 102 or being re-circulated throughthe tank 104. In another embodiment, the component 134 may include afilter or additive station. A filter may remove certain components fromthe pumped materials while an additive station may add certaincomponents. By way of example, the additive station may be used to addanaerobic microorganisms into the tank 104. In other embodiments,methanol may be added. Methanol may, for instance, act as a stabilizeror catalyst to improve the efficiency or speed of anaerobicmicroorganisms in breaking down the VOCs or other HAPs within the tank104. Of course, the component 134 may also include other elements,including burner, clarifier, chiller, or the like. Any combination ofsuch elements may also be used.

Although the output of the pumps 130, 132 are shown as each passingthrough the component 134, such an embodiment is merely illustrative. Inother embodiments, one or both outputs may bypass the component 134. Instill other embodiments, outputs from one or both of the pumps 130, 132may selectively bypass the component 134.

The system 100 may include additional or other components, subsystems,devices or elements in addition to, or instead of, those described. FIG.1, for instance, illustrates an outlet 136 for the tank 104, whichoutlet 136 may be used to drain the tank 104 or otherwise removematerial therefrom. In accordance with some example embodiments, theoutlet 136 may allow materials to be removed from the tank 104 and movedto another location where the wastewater 120 and/or sludge 124 may beprovided to additional tanks, ponds, vessels, or devices that filter,dry, burn, treat or otherwise process the wastewater 120 and/or sludge124. The outlet 136 may also have a valve (not shown) which may beseparate from, or included with, the valving station 128.

FIG. 1 illustrates an example system that may generally represent anynumber of different types of bioreactor systems. In one embodiment, thebioreactor system 100 may encompass a small-scale system. In such asystem, tanks 102, 104 may have a relatively small size, and can, by wayof example, have a volume on the order of one barrel to thousands ofbarrels. As a more particular example, the tanks 102, 104 may have avolume between about one hundred barrels and about a thousand barrels.More particularly still, an example embodiment may include a so-called“frac tank” of a type commonly used in the oil and gas industry, thevolume of which may be between about 300 barrels and about 500 barrels(e.g., 400 barrels).

Because of its size, the bioreactor system 100 shown in FIG. 1 may berelatively portable (e.g., be transported on a trailer; comprise part ofa tanker, such as a tanker trailer or tanker truck; etc.). Theportability of a bioreactor system 100, or its components, may enablewastewater 120 or other wastewater that includes dissolved VOCs to betreated at or near the site from which such water is obtained. In otherembodiments, wastewater 120 may be treated at a location remote from thelocation where it is obtained, or the tanks 102, 104 may be difficult orimpossible to transport. More particularly still, some embodiments ofthe tanks 102, 104 contemplate use of the bioreactor system 100 on alarger scale, such as where the tanks 102, 104 may represent fluidreservoirs such as ponds.

Turning now to FIG. 2 an embodiment of a water treatment site isillustrated and includes a bioreactor system 200 configured for thelarge scale treatment of wastewater. Like a smaller version that may berepresented by the bioreactor system 100 shown in FIG. 1, the bioreactorsystem 200 includes a fluid reservoir 202 having an inlet 206 and anoutlet 208. Moreover, the bioreactor system 200 also includes a fluidreservoir 204, which can act as a bioreactor, and which includes a setof inlets 210, 212 and outlets 214-218. The fluid reservoir 204 may actas a large-scale bioreactor configured to collect large amounts of water(e.g., wastewater, etc.). Such collection may occur on a substantiallycontinually basis. An example fluid reservoir 204 could potentiallyprocess a thousand or more barrels of wastewater each day.

The bioreactor system 200 also includes anaerobic microorganisms 222 fortreating water within the interior of the reservoir 204. In addition,the bioreactor system 220 may include other components that interactwith the fluid reservoir 204, including a sludge collection system thatcommunicates with the outlet 218 and/or the bottom of the reservoir 204,a mixing system, a leak detection system, a valving system 228, or anycombination of the foregoing. Embodiments of some of these additionalcomponents are described in additional detail in U.S. patent applicationSer. No. 61/677,004, filed on Jul. 30, 2012, which application is herebyexpressly incorporated herein by this reference in its entirety.

The illustrated valving system 228 may also be similar to the valvingstation 128 represented in FIG. 1. Thus, the illustrated valving systemincludes a set of pumps 230, 232 that communicate with inlets 210, 212and outlets 216, 218 of the bioreactor reservoir 204 and with the outlet208 of the feed reservoir 202. Such components may allow the transportof untreated wastewater 220U to the bioreactor reservoir 204, as well asthe re-circulation of treated wastewater 220T in the bioreactorreservoir 204. Untreated or treated wastewater may also be heated,cooled, or otherwise conditioned (e.g., to maintain the treatedwastewater 220T at a desired temperature) using a conditioning element234 of the valving station 228.

Various parameters, such as the amount of pressure generated by thepumps 230, 232, the orientations and locations of the outlets 216, 218and the inlets 210, 212, may dictate the manner in which fluids movethrough (e.g., are circulated within, etc.) the interior of thebioreactor reservoir 204. Such movement may homogenize the contents ofthe treated wastewater 220U and facilitate (e.g., increase the rate of,etc.) removal of VOCs from the wastewater.

The anaerobic microorganisms 224 of the bioreactor reservoir 204 mayalso have characteristics that are the same as or similar to theanaerobic microorganisms 122 of the bioreactor reservoir 104 describedin reference to FIG. 1. For example, the anaerobic microorganisms 122,222 may reduce levels of dissolved VOCs, such as the BTEX materials, inwastewater, including in wastewater collected during oil or gasexploration or production operations.

Because the bioreactor system 200 is large, the reservoirs 202, 204 mayalso be large. In various embodiments, the fluid reservoirs 202, 204 ofa large bioreactor may comprise a pool or, as depicted, a pond. Forsimplicity, the fluid reservoirs 202, 204 may each be referred to hereinas a “pond”, although the fluid reservoirs 202, 204 are not limited toany particular structure or form.

A pond, which may comprise a recessed area formed in the ground, may beconstructed to have any desired capacity. Without limitation, one orboth of the ponds 202, 204 may have a capacity of one thousand barrelsor more. In some embodiments, the volume of the ponds 202, 204 may beten thousand barrels or more, or even fifty thousand barrels or more(e.g., fifty-five thousand barrels). While various configurations ofponds 202, 204 are within the scope of this disclosure, relativelyshallow ponds with relatively large surface areas may be used in someembodiments, as larger surface areas may support more of the anaerobicbacteria 224 of the bioreactor pond 204. Optionally, the ponds 202, 204may have a liner or barrier (not shown) to prevent dissolved VOCs orother potential pollutants in the wastewater from seeping into theground in which the ponds 202, 204 are located. Similarly, a cover (notshown) may also be placed over the ponds 202, 204 to restrict VOCs orother pollutants from escaping into the atmosphere.

As shown in FIG. 2, the bioreactor system 200 may include a number ofadditional reservoirs, including additional or other ponds, tanks, orthe like. The bioreactor system 200 may operate as a full-scalewastewater treatment facility or wastewater treatment site. In such anembodiment, untreated wastewater 220U obtained from whatever source maybe transported to the facility. In FIG. 2, the wastewater 220U may betransported using a tanker 238. A hose or other conduit on the tanker238 may couple to a fitting leading to an inlet 240 to a fluid reservoir242. In embodiments where the untreated wastewater 220U is transportedfrom another component of a system or site where the bioreactor pond 204is located, the inlet 240 may comprise a channel or a conduit thatenables the untreated wastewater 220U to flow from an upstream locationto reservoir 242.

The reservoir 242 may have any number of different structures orpurposes. For instance, the reservoir 242 may be a storage tank, vaultor separator. A vault or separator may perform some initial separationof wastewater from hydrocarbons and sludge. Untreated wastewater 220Ufrom the reservoir 242 may also or instead be directed to anotherreservoir, such as the feed pond 202. The feed pond 202 may also be aso-called “skim pond” which further facilitates some separation ofwastewater from hydrocarbons and/or sludge, as described in greaterdetail hereafter. Separated wastewater may then be transferred out ofthe outlet 208 and to the bioreactor pond 204, optionally with theassistance of the valving system 228.

In accordance with some embodiments of the present disclosure, thereservoir 242 may act as a separator holding several hundred, or even athousand or more, barrels of liquid. Wastewater may be accompanied bylight non-aqueous phase liquids (LNAPLs) (e.g., hydrocarbons, etc.) anddense non-aqueous phase liquids (DNAPLs) (e.g., paraffins, etc.), solidmaterials (i.e., sludge), and the like. The reservoir 242 may be thefirst component of the water treatment site where wastewater isprocessed. Specifically, the reservoir 242 may act as a separatorconfigured to receive wastewater and to hold the wastewater for asufficient period of time to enable the LNAPLs, water and sludge toseparate. In some embodiments, the reservoir 242 is positioned at alocation accessible to large trucks and tractor-trailers such as thetanker 238. The reservoir 242 may also be positioned at a higherelevation than other downstream components in order to facilitate flowof wastewater 120 through the water treatment site.

Wastewater 220 may be communicated from the reservoir 242 to the feedpond 202 through a pipe, hose or other conduit 243, and optionally oneor more valves (e.g., valves in or separate from the valving system228). At the feed pond 202, which may be acting as a skim pond, furtherseparation of residual LNAPLs (e.g., hydrocarbons, etc.) and sludge(e.g., DNAPLs, solids, etc.) from the water may be achieved. The feedpond 202 may be significantly larger than a reservoir 242 acting as aseparator. Thus, the wastewater may reside in the feed pond 202 for amuch longer period of time than it may reside within the reservoir 242,without disrupting the rate at which wastewater may be delivered to andtreated by the wastewater treatment site. The skim pond 202 may, in someembodiments, have a capacity of 10,000 barrels or more (e.g., 50,000barrels, 80,000 barrels, 100,000 barrels, etc.).

Since the primary purpose of a skim pond is to enable further separationof LNAPLs, such as hydrocarbons, and sludge from the wastewater,hydrocarbon and sludge collection systems may also be associated withthe feed pond 202. LNAPLs may be removed from the feed pond 202 in anysuitable manner. As an example, an auto-skimmer of known type may beused to remove LNAPLs from the surface of the wastewater. As anotherexample, LNAPLs may be separated from wastewater at an outlet of thefeed pond 202. Any LNAPLs collected from the feed pond may be placed ina collection tank and, ultimately, transported to a storage tank wherethe LNAPLs will be stored until sufficient volumes are collected tojustify their transportation from the water treatment site to arefinery.

After separation in the feed tank 202, untreated wastewater 220U may beremoved therefrom through an outlet 208 of the feed pond 202. In thedepicted embodiment, one or more valves or components of a valvingsystem 228 may control the flow of untreated wastewater 220U out of thefeed pond 202 to downstream locations, including to an inlet 210 of thebioreactor pond 204. In the bioreactor pond 204, untreated wastewater220U may be treated using anaerobic microorganisms that digest VOCs andother materials and convert them into less harmful substances (e.g.,carbon dioxide, water vapor, and methane).

Following treatment in the bioreactor pond 204, the wastewater may betreated wastewater 220T that can be transferred from the bioreactor pond204 to still another component 244. An outlet 246 of the pond 204enables treated wastewater 220T to be removed from the interior of thebioreactor pond 204. The component 244 to which the treated wastewater220T is directed may have any number of different purposes or includedifferent elements, including hydrocarbon removal components, storagetanks, burners, filters, and the like. For instance, the component 244may be a filter configured to remove at least some HAPs, including someVOCs, from the water. Without limitation, the component 242 may be afilter configured to remove some toluene, ethylbenzene and xylene fromthe treated wastewater 220T. Treated wastewater 220T may also, in otherembodiments, be allowed to bypass the filter or other component 242. Instill further embodiments, the component 242 acts as a clarifier toremove sludge from treated wastewater 220T, which sludge may optionallybe conveyed back to the bioreactor pond 204.

From the component 244, the treated wastewater 220T may further beconveyed to other locations, including to one or more evaporation ponds248, 252 using outlets 250, 254. Each evaporation pond 248, 252 may belocated at a lower elevation than the bioreactor pond 204 and/or thefilter or other component 242, and may be configured in a manner knownin the art. In embodiments where a wastewater treatment site includes aplurality of evaporation ponds 248, 252, each evaporation pond may belocated at a lower elevation than the preceding pond. In order, upstreamto downstream, the LNAPL content in wastewater decreases from oneevaporation pond to the next, while the content of TDSs, including salt,in the water increases. More specifically, each evaporation pond 248,252 may be configured to receive wastewater with reduced,environmentally acceptable levels of dissolved VOCs, or “treated water,”and to gradually introduce the treated water back into the environment(e.g., through evaporation into the air or reintroduction into surfacewater), after the water complies with governmental regulations.

When the component 242 and evaporation ponds 248, 252 are located atprogressively lower elevations, the outlets 246, 250, 254 may exploitthe use of gravity to move water therebetween, and can use one or morevalves to control such a flow. The valves may, but need not necessarily,be part of the valving system 228. In other embodiments, pumps, whetheror not part of the valving system 228, may enable the treated wastewater220T to be removed from the bioreactor pond 204 and/or transportedthrough successive downstream components. Combinations of gravity feedand pump systems may also be used.

The outlet 246 may comprise a channel or conduit that enables thetreated wastewater 220T to flow to the downstream filter or othercomponent 244. Optionally, the outlet 246 may be located at or near thebottom of the pond 204 and extend to a location at or near the top ofthe component 244. In such an embodiment, the configuration and/ororientation of the liquid outlet 246 may clarify the treated wastewater220T as it is removed from the bioreactor pond 204. Outlet 250 betweenthe component 244 and the evaporation pond 248 and/or the outlet 254between the evaporation ponds 248, 252 may be similarly constructed.

Gasses that are generated within the bioreactor pond 204, includingproducts of the metabolism of VOCs, may be collected through one or moregas outlets 214 of the bioreactor pond 204. Each gas outlet 214 maycommunicate with or comprise a conduit that vents gasses and, in someembodiments, transports the gasses to one or more locations where theymay be collected or processed. In this embodiment, the vented gasses maybe transported to a storage container 256, although the vented gassesmay be transported to any number of different locations, containers, orcomponents.

It may be desirable to maintain a flow of liquids within the interior ofa bioreactor system (e.g., within bioreactor pond 204 or bioreactor tank104), or to otherwise condition the wastewater so as to facilitatebioreactive processes. Accordingly, a conditioning system may optionallybe provided. The valving stations in FIGS. 1 and 2 represent someexamples of conditioning systems. Such systems may provide, forinstance, a continuous, occasional or periodic flow of liquids into andout of the interior of a bioreactor. A variety of different types ofmixing systems may be employed as will be appreciated by those ofordinary skill in the art. In some embodiments, conditioning systems mayalso include other components, including heating elements, additivestations, and the like.

Turning now to FIG. 3, a bioreactor system 300 is schematicallyillustrated and includes an example valving station 328. The valvingstation 328 is an example of one type of conditioning system that may beused to facilitate treatment of wastewater within the bioreactor system300.

In this particular system, the valving station 328 is positioned betweena feed reservoir 302 and a bioreactor reservoir 304 so as to allowwastewater or other materials within the feed reservoir 302 to passthrough the valving station 328 and thereafter into the bioreactorreservoir 304. Optionally, the valving station 328 may also allowmaterials already within the bioreactor reservoir 304 to be circulatedout of the reservoir 304, through the valving station 328, and back intoreservoir 304. While reservoirs 302, 304 are schematically illustratedas open reservoirs, it should be appreciated that such an embodiment ismerely illustrative. In other embodiments, for instance, the reservoirs302, 304 may be substantially closed, such as in the case of a tank or acovered pond.

In this embodiment, the feed reservoir 302 includes an outlet 308through which wastewater or other materials may be fed into the valvingstation 328. Within the valving station 328 are two pumps 330, 332.According to the illustrated embodiment, the pump 332 may communicatewith the outlet 308. The pump 332 is configured to draw fluids from theinterior of the feed reservoir 302 and move them to an outlet 358 of thepump 332, which outlet may ultimately lead to an input (e.g., input 310or 312 a) of the bioreactor reservoir 304.

When fluids exit the pump 332 at the outlet 358, the fluid from the feedreservoir 302 may move along any of one or more different paths. In FIG.3, for instance, the pump outlet 358 may branch or split into twochannels or conduits 358 a, 358 b. Fluid passing through the channel 358a, for instance, may move directly to an input 310 to the bioreactorreservoir 304. In contrast, fluid passing through the channel 358 b mayfollow a different route and pass through additional or othercomponents.

In FIG. 3, for instance, the valving station 328 includes a heatingelement 360. The heating element 360 may be in-line with the channel 358b. As a result, fluid drawn from the feed reservoir 302 may pass throughthe pump 332 and into the heating element 360. Such fluid may there beheated to be within a desired temperature range. Thereafter, the fluidcan be expelled from the heater 360 through an output channel 362 thatleads to an input 312 a of the bioreactor reservoir 304.

Including a heating element 360 within the valving station 328 of thepresent embodiment allows for a variety of actions to take place toenhance the efficiency of the bioreactor system 300. For instance,anaerobic microorganisms such as mesophilic bacteria may digest VOCs andother materials when the wastewater is at a temperature range between35° F. and 100° F. At the lower end of the spectrum, however, thebacteria may operate at lower efficiency. Digestion of VOCs may be low,and consequently the production of biogas may be low. It may thereforebe beneficial to increase the temperature of the wastewater to improvedigestion and biogas production.

At times, however, the temperature of the wastewater in the feedreservoir 302 may be suitable for efficient treatment in the bioreactorreservoir 304. In that case, the wastewater may bypass the heatingelement 360 (e.g., by following output 358 a). To bypass the heatingelement 360, a stop valve 364 on the channel 358 b may be activated, sothat all flow is diverted to the channel 358 a, which flow does notextend through the heating element 360.

As further discussed herein, other aspects of the present disclosurecontemplate mixing contents of the bioreactor reservoir 304. Mixing thecontents of the bioreactor reservoir 304 may distribute the anaerobicmicroorganisms throughout the reservoir 304, thereby allowing themicroorganisms to find and feed on VOCs and other digestible materials.

The valving station 328 of FIG. 3 also includes a pump 330 that may besolely or primarily used for re-circulating and mixing materials withinthe bioreactor reservoir 304. In this embodiment, the pump 330 may be incommunication with one or more outlets 316, 318 of the bioreactorreservoir 304. Such outlets 316, 318 may provide access to differentmaterials within the reservoir 304. For instance, the outlet 316 may belocated at or near the bottom of the reservoir 304, where suction fromthe pump 330 may pull solid materials and sludge. The outlet 318 may beat an intermediate location on the reservoir 304 so as to allow liquidmaterials, including wastewater being treated, to be pulled therefrom.

Wastewater and potentially solid materials drawn from the bioreactorreservoir 304 may move through the pump 330 and to an outlet channel364. The outlet channel 364 may follow a single path or may branch intotwo or more paths. In FIG. 3 there are two channels 364 a, 364 bbranching from the outlet channel 364, although more or fewer than twobranching channels may be available.

As with the outlet channel 358 of the pump 332, the outlet channel 364may branch into paths, one or more of which may pass through a heatingelement 360. In this embodiment, the same heating element 360 used forheating materials passing through the pump 332 may also heat materialspassing through the pump 330. In other embodiments, separate heatingelements may be used.

More particularly, in the illustrated example, the channel 364 a mayallow pumped materials to pass directly from the pump 330 to an input312 b of the reservoir 304. In contrast, the channel 364 b may sendmaterials into the heating element 360. As discussed above, wastewaterand other materials may be more effectively treated using some anaerobicmicroorganisms when the treated materials are in a desired temperaturerange. Materials within the bioreactor reservoir 304 may be at atemperature below the desired range, or may cool while beingre-circulated. In one embodiment, the reservoir 304 may itself act as aheat sink so that heat is drawn out from the wastewater or othermaterials within the reservoir 304. By passing re-circulated materialsthrough the heating element 360, the wastewater and other materials canbe brought to a desired temperature. Materials may exit the heatingelement 360 through the output channel 362 where they are directed intoan input 312 a of the bioreactor reservoir 304.

While one pump (i.e., pump 332) may be used as a feed pump for feedingwastewater from the feed reservoir 302 to the bioreactor reservoir 304,and a second pump (i.e., pump 330) may be used to pump and re-circulatematerials within the bioreactor reservoir 304, such an embodiment ismerely illustrative. In other embodiments, for instance, the same pumpmay both feed materials to, and re-circulate materials within, thebioreactor reservoir 304.

As an example, FIG. 3 illustrates the outlet 318 of the bioreactorreservoir 304 as potentially branching into two channels 318 a, 318 b.One channel 318 a may feed into one inlet of the pump 330. An optionalsecond channel 318 b may feed into one inlet of the pump 332. Thus, eachof the pumps 330, 332 optionally include multiple inputs. Moreparticularly, the inputs to the pump 330 may include wastewater andsolid material from the bioreactor reservoir 304, while the inputs tothe pump 332 may include wastewater from the feed reservoir 302 as wellas wastewater from the bioreactor reservoir 304.

When multiple inputs are provided to one or both of the pumps 330, 332,the pumps 330, 332 may simultaneously draw from the multiple sources, ormay selectively draw from only a single source. In FIG. 3, the variousoutputs and channels 308, 316, 318 a, 318 b leading to the pumps 330,332 may have respective stop valves 366 thereon. If, for instance, it isdesired to use the pump 332 to only feed wastewater from the feedreservoir 302 to the bioreactor reservoir 304, the stop valve 366 on thechannel 318 b may be used to close the channel 318, thereby allowingsuction to only draw from the feed tank 302. Similarly, if the stopvalve 366 on the channel 316 is closed, the pump 330 may draw only thewastewater from the bioreactor reservoir 304, without also drawing thesludge or other solid materials. Thus, materials input into the valvingstation 328 by the pumps 330, 332 may be limited to a single source foreach pump. Alternatively, the inputs may allow multiple simultaneousinputs for each pump.

Stop valves 366 may also be positioned on the channels 358 a, 358 b, 364a, 364 b, and used to control the direction and conditioning of thepumped materials. In particular, by closing one valve, materials may berestricted from flowing through the heating element 360, or restrictedfrom bypassing the heating element. By way of illustration, if the stopvalve 366 on the channel 358 b is closed, the materials (e.g., feedmaterials from the feed reservoir 302 or re-circulated materials fromthe bioreactor reservoir 304) may instead flow through the channel 358 aand directly to the input 310 of the bioreactor reservoir. A similareffect may be produced by closing the stop valve 366 on channel 364 b,in which case re-circulated materials may pass through the channel 364 aand into the bioreactor reservoir 304 through input 312 b. Conversely,by closing stop valves 366 on channels 358 a, 364 a and opening the stopvalves 366 on the channels 358 b, 364 b, the pumped materials may beforced through the heating element 360 to be conditioned by heating thematerials to a desired temperature. The stop valves 366 may therefore beselectively actuated to direct the flow of materials into the pumps 330,332 and/or the heating element 360.

As a more particular example, each of the stop valves 366 may beselectively operated and opened or closed in a manner that controlsaccess to, and the destination of, water flowing through the valvingstation 328. For instance, where the stop valves 366 on channels 308,318 b are each open, the pump 332 may draw from both the feed reservoir302 and the bioreactor reservoir 304. Such fluids may then be combinedand sent to the heater 360 for conditioning, when the stop valve 366 onchannel 358 b is open. Alternatively, if the stop valve 366 on channel358 b is closed and the stop valve 366 on channel 358 a is open, thecombined fluids may bypass the heating element 360 and flow throughinlet 310 back into the bioreactor reservoir 304. Of course, byselectively closing one or both of the stop valves 366 on channels 308,318 b, the sources of wastewater can be changed. A similar process mayalso be obtained by selectively closing the stop valves 366 on channels316, 318 a, 364 a and 364 b with respect to wastewater and/or solidmaterials pumped by the pump 330.

In some embodiments, an operator of the bioreactor system 300 may wantor need to determine the conditions present within the bioreactorreservoir 304 and/or the feed reservoir 302. To assist in such a task,the valving station 328 may also include one or more sampling lines 368a-368 c. The illustrated sampling lines 368 a-368 c may each allowsampling and/or testing of certain materials flowing through the valvingstation 328. For instance, the sampling line 368 a is connected to theoutput 364 a from the re-circulation pump 330, and allows sampling ofwastewater, solid materials, or a combination thereof that arere-circulated using the pump 332 and which bypass the heating element360. Similarly, the sampling line 364 b is connected to the output 358 afrom the pump 332, and allows sampling of untreated wastewater,re-circulated wastewater, or a combination thereof, and which alsobypass the heating element 360. In contrast, the sampling line 368 c maybe connected to the output 362 from the heating element 360. Thus,untreated wastewater from the feed reservoir 302, or re-circulatedwastewater and/or solid materials from the bioreactor reservoir 304, orsome combination thereof, may be sampled after it is heated using theheating element 360.

Various stop valves 366 on the sampling lines 368 a-368 c may be used toselectively open and close the sampling lines 368 a-368 c as needed.When one or more stop valves 366 are opened, materials passingtherethrough may be directed to a desired source. In this embodiment,for instance, the sampling lines 368 a-368 b are directed to a drain370, although a reservoir, vessel or other element may also be used toreceive materials through a sampling line 368 a-368 c.

As will be appreciated by those skilled in the art in view of thedisclosure herein, the valving station 328 may allow an operator of awastewater treatment facility to effectively and efficiently treatwastewater, even when environmental conditions change. As an example,when wastewater in a bioreactor reservoir 304 and/or feed reservoir 302are already at a desired temperature (e.g., during warmer times of theday or year), the valving station 328 may allow a heating element 360 toeffectively be shut-down so that wastewater bypasses the heating element360. Conversely, when wastewater is colder (e.g., during colder times ofthe day or year), the heating element 360 may be selectively activatedand the flow of materials may pass through the heating element 360.

The valving station 328 also offers flexibility with respect to when andhow materials are moved to or within the bioreactor reservoir 304. As anexample, as the illustrated system includes two pumps 330, 332, eachpump may be operated at different times, have different capabilities, orserve different purposes. If, for instance, one of the pumps fails,materials may still be re-heated as pumped using the other pump.Materials may be fed or re-circulated by the other pump as well.Moreover, according to some embodiments, pumping of solid materials mayrequire a higher power pump than pumping other materials, such aswastewater from the feed reservoir 302 and/or the bioreactor reservoir304. A pump (e.g., pump 330) for pumping solid materials may thereforebe larger or more powerful than a pump (e.g., pump 332) for pumpingmaterials that are less dense or viscous. By selectively using thelower-powered pump when available, power requirements for the bioreactorsystem 300 may be reduced.

The example system of FIG. 3 is but one example of a suitableconditioning system that may be used in connection with a bioreactorand/or wastewater treatment facility. In other embodiments, forinstance, additional or other components may be provided. A chiller orcooler may be provided where, for instance, it is desirable to reduce atemperature of feed wastewater and/or re-circulated wastewater. Filters,burners, driers, or other components may also or alternatively beprovided.

In addition, the valving within a conditioning system may be varied inany manner of different ways. To illustrate one example, FIG. 4 providesa schematic illustration of another bioreactor system 400, which systemmay be operated in a manner similar to that of the bioreactor system 300of FIG. 3. In particular, the bioreactor system 400 provides a valvingstation 428 which can perform the same or similar functions as thevalving station 328, but with different valving aspects.

More particularly, a feed reservoir 402 may include an outlet 408 whilea bioreactor reservoir 404 includes a plurality of outlets 416, 418.Optionally, one or more of the outlets split into multiple channels orlines (e.g., outlet 418 to outlets 418 a, 418 b). The various outlets408, 416, 418 may be directed into a manifold 472. The manifold 472shown in FIG. 4 may allow the four inputs and can provide two outputchannels 476 a, 476 b, each of which leads to a pump 430, 432.

The manifold 472 may act as a valve to determine which inputscommunicate with respective pumps 430, 432. For instance, theillustrated manifold 472 may be used to allow one, none or both of theoutput 408 from the feed reservoir 402 and/or output 418 b from thebioreactor reservoir 404 to communicate with the pump 432 (e.g., toallow suction drawing fluid towards the pump 332). Similarly, themanifold 472 may allow one, none, or both of the output 418 a carryingre-circulated waste water and/or output 416 carrying re-circulated solidmaterials to communicate with the pump 430 (e.g., to allow suctiondrawing fluid or other materials towards the pump 430). The manifold 472may be operated manually or automatically. For instance, an electroniccontrol system 474 may determine which valves within the manifold 472should be opened for a desired condition (e.g., that feed materials fromthe feed reservoir 402 should be the only materials passed to the pump332 and/or that wastewater and solid materials should be re-circulatedusing pump 330).

Depending on the conditions set by the manifold 472, the pumps 430, 432may pump different types of material through corresponding outlets 464,458, each of which may lead to a second manifold 478. The secondmanifold 478 may also act as a valve to determine which of differentdirections inputs should be directed. As shown in FIG. 4, for instance,the output channel 458 may be selectively directed by the manifold 478to provide fluid to a first output channel 458 a which bypasses aheating element 470, or to a second output channel 458 b which can bedirected to the heating element 470. Similarly, the output channel 464may pass fluid into the manifold 478 and the manifold 478 determineswhether the fluid bypasses the heating element 470 (i.e., is output tochannel 464 a) or is directed to the heating element 470 (i.e., isoutput to channel 464 b).

Optionally, if two or more channels are to be directed to the heatingelement 470, and additional valve 480 or manifold may be provided toselectively combine the flow into a single output 482 that is thenpassed into the heating element 470. Of course, in other embodiments,the heating element 470 may allow multiple inputs or there may bemultiple heating elements 470.

Fluids and other materials that pass through the heating element 470, orwhich bypass the heating element 470, may be directed into thebioreactor reservoir 404. In accordance with one embodiment, such asthat in FIG. 3, each channel for a fluid or other material may providean individual input to the bioreactor reservoir 404. In otherembodiments, however, one or more channels may be combined into a singleinput. FIG. 4, for instance, illustrates an additional valve 484 ormanifold which can be used to combine the flow from multiple channels.In particular, the valve 484 may receive materials from the channels 458a, 464 a which include materials pumped by pumps 432 and 430,respectively, and which bypass the heating element 470. Additionally, oralternatively, the valve 484 may include an input from the channel 462which originates from the heating element 470. Any or all flows maycombine within the valve 484 and be directed to an output 486 whichconnects to an input 410 of the bioreactor reservoir 404.

Sampling lines 468 a-468 c and corresponding stop valves 466 may also beconnected to various output channels, and can optionally lead to a drain471. The operation of the sampling lines 468 a-468 c may be similar tothat of the sampling lines described in FIG. 3. In other embodiments,however, rather than including individual stop valves 466, a samplingmanifold (not shown) may be used to provide collective control over thesampling lines 468 a-468 c.

Those skilled in the art will appreciate, in view of the disclosureherein, that the system 400 may provide centralized control of theoperation of one or more aspects of the valving station 428. Inparticular, rather than operating each output or fluid lineindividually, one or more manifolds or valves may collectively controlwhich fluids are drawn and/or the direction drawn fluids travel. Thus,if a system operator wants to draw only fluid from the feed tank 402,the manifolds and valves within the valving station 428 canautomatically or manually be set to do so, optionally with the abilityto also control whether or to what extent certain conditioning (e.g.,heating) occurs. Similar control may be used to determine which pumphandles transfer of fluids and/or whether multiple fluids can betransferred simultaneously.

Moreover, although aspects of the present disclosure include a valvingstation 428 which is between the feed reservoir 402 and the bioreactorreservoir 404, this should not be interpreted as requiring the valvingstation 428 have any particular physical location. Instead, the valvingstation 428 may be between the feed reservoir 402 and the bioreactorreservoir 404 in terms of fluid flow, such as when downstream from thefeed reservoir 402 and upstream relative to the bioreactor reservoir404. In some embodiments, the valving station 428 may even be physicallyformed as part of the feed reservoir 402 or the bioreactor reservoir404, with components in multiple physical locations, at an off-sitelocation, or in other manners.

With continued reference to FIG. 4, various elements of a method fortreating wastewater (in addition to those that should already beapparent from the foregoing description) and maintaining wastewater at adesired temperature are now described. Such method may be fully orpartially performed at a wastewater treatment facility using either alarge-scale bioreactor system (e.g., bioreactor system 200) or a smallerscale system (e.g., bioreactor system 100). Additionally, whiledescribed in the context of the bioreactor system 400 of FIG. 4, themethod may also be performed in the bioreactor system 300 of FIG. 3, orany other way, regardless of the environment in which the bioreactorsystem is situated.

Initially, wastewater may be provided (e.g., through a tanker, at thelocation of the treatment facility, etc.). Wastewater that is providedmay be accessed and LNAPLs and, optionally, sludge may be separated fromthe wastewater. Separation may be achieved by any suitable means,including using a separator, skim pond, or other component describedherein or known in the art. Separation may be effected by gravity,centrifugation or any other suitable technique. Separation may, forinstance, occur in a separator over a sufficient period of time (e.g., afew hours, a few days, etc.) to enable LNAPLs (e.g., oil, gas, otherhydrocarbons, etc.) that have mixed with the wastewater to separate fromthe wastewater. Once LNAPLs have separated from the wastewater, they maybe removed and optionally stored. In addition to allowing LNAPLs toseparate from the wastewater, sludge (e.g., DNAPLs, solids, etc.) maydrop to the bottom of the separator while the wastewater sits therein.The solids, which may be referred to as “sludge,” may be periodically oroccasionally collected.

Following the initial, rough separation of LNAPLs and sludge from thewastewater, as well as any optional flaring, further separation ofLNAPLs and/or sludge from the wastewater may occur. In some embodiments,the wastewater may reside within the feed reservoir 402, which may actas a skim pond in some embodiments. The water may reside for a prolongedperiod of time, and any LNAPLs that collect at the surface of thewastewater may be collected and potentially stored. Any solids that dropto the bottom of the feed reservoir 402 may remain there until thesolids, or sludge, is removed. The recovered sludge may be used forother purposes; for example, to form hardened roadway surfaces (e.g., atoil or gas exploration or production facilities, etc.).

The wastewater in the feed reservoir 402 may be accessed and may beexamined to determine whether or not it is suited for introduction intothe bioreactor reservoir 404 (e.g., to determine if sufficientseparation has been achieved and LNAPLs have been removed), or todetermine how it should be introduced into the bioreactor reservoir 404.As an example of such examination, the wastewater may be tested for thepresence of biocides, which are sometimes added to water used duringexploration and/or production. If undesirably high levels of biocidesare detected (e.g., sufficient levels to disturb the anaerobicmicroorganisms of the bioreactor reservoir 404, etc.), the wastewatermay bypass the bioreactor reservoir 404 and proceed to alternativetreatment components. As another example, if the salt and/or TDS contentof the wastewater is undesirably high (e.g., at or above a level thatwould have a detrimental effect on the anaerobic microorganisms), thevolume of wastewater introduced into the bioreactor reservoir 404 may belimited (e.g., to an amount that will not increase the salt or TDScontent of the wastewater by more than a fixed amount (e.g., fivepercent, ten percent, etc.) until wastewater with a lower salt or TDScontent is available). Alternatively, fresher water may be added towastewater with a high salt content or TDS content to dilute the same.As another alternative, such wastewater may bypass the bioreactorreservoir 404.

In some embodiments, other characteristics of the wastewater may bedetermined. For instance, a temperature of the wastewater may bemeasured. If the temperature is too low or environmental or otherconsiderations indicate that the wastewater may be undesirably cool, thewastewater may be heated. Conversely, if the temperature is too high,the wastewater may be chilled or cooled. To perform such a function, thevalving station 428 may use manifold 472 as a valve to open flow fromthe feed reservoir 402 to a pump 432. Untreated wastewater from the feedreservoir 402 may pass from the pump 432 to a fluid output 458, and to asecond manifold 478. The second manifold 478 may also act as a valve todetermine whether the untreated wastewater should be directed to aheating element 460, or should bypass the heating element 460. When themanifold 478 opens the conduit to the heating element 460, the untreatedwastewater may be heated to a desired temperature. Thereafter, theheated, untreated wastewater may be output along a channel 462 andultimately to an input 410 to the bioreactor reservoir. As notedpreviously, one or more additional manifolds or valves (e.g., valves480, 484) and channels (e.g., channels 482, 486) may also be used toconvey the untreated wastewater to a heating element and/or to thebioreactor reservoir 404. At the bioreactor reservoir, anaerobicmicroorganisms may then be used to treat the wastewater and reduce acontent of VOCs in the wastewater.

Alternatively, if the temperature or other condition of the wastewaterobtained from the feed reservoir 402 is satisfactory, the heatingelement 460 and/or other conditioning element may be bypassed. In FIG.4, for instance, the manifold 478 may open a valve to channel 464 a andclose a valve to channel 464 b, thus allowing the unconditionedwastewater to flow through the valve 484 and channel 486 to the input410 to the bioreactor reservoir.

In addition to, or instead of, feeding wastewater from the feedreservoir 402 to the bioreactor reservoir 404, wastewater and/or sludgein the bioreactor reservoir 404 may be re-circulated and optionallyconditioned. As an example, in some embodiments, a temperature or othercharacteristic of the wastewater may be determined or assumed. If thetemperature is too low or the environmental conditions suggest thewastewater may be undesirably cold, the wastewater may be heated,whereas if the temperature is too high, the wastewater may be chilled orcooled. To perform such a function, the valving station 428 may use themanifold 472 as a valve to open flow from the bioreactor reservoir 404to the pump 432. If the manifold closes the channel to the feedreservoir 402, the treated wastewater may be pumped through the systemas previously described, such that re-circulated, treated wastewater maybe selectively conditioned or may bypass conditioning. If both valves(i.e., the valves to the feed reservoir 402 and to the bioreactorreservoir 404) are open, the wastewater may be combined when eitherbeing conditioned (e.g., treated by heating element 470) or not.

Alternatively, rather than using the pump 430, the untreated wastewaterfrom the bioreactor reservoir 404 may be moved by the pump 430. Inparticular, wastewater and/or sludge may be transferred by the pump 430,depending on whether the manifold 470 opens or closes valvescorresponding to the channels 416, 418 a. The wastewater and/or sludgemay then be conveyed by the pump 430 and output to a channel 464. Thesecond manifold 478 may then control whether the wastewater and/orsludge output in channel 464 should be directed to or around the heatingelement 460. If the heating element is to be used (e.g., to heat ormaintain a temperature of the wastewater), the manifold 478 may open acorresponding valve leading to a channel 464 b, and ultimately to theheating element 460 as described above. Alternatively, if the heatingelement is not to be used (e.g., the temperature is already sufficientlyhigh, the sludge or material is too viscous for the heating element 460,etc.), the manifold 478 may close a valve leading to the channel 464 band open a channel 464 a leading through a valve 484 and to the input410 to the bioreactor reservoir 404.

Using the above method, the temperature of the wastewater being treatedin the bioreactor reservoir 404 may be maintained at a desiredtemperature, whether by heating untreated wastewater from the feedreservoir 402, heating re-circulated wastewater or sludge from thebioreactor reservoir 404, or both. Moreover, such a system may use thesame heating element to selectively heat either or both components,although in other embodiments different heaters may be used. Bymaintaining the temperature within a desired range, the anaerobicmicroorganisms in the bioreactor reservoir 404 may operate at a moreeffective level to break down VOCs and/or to produce high grades ofbiogas. All or substantially all gases and vapors that are presentwithin the bioreactor reservoir 404 may be removed therefrom, creating asubstantially or totally anaerobic environment. Gasses may becontinually drawn, or drawn when exceeding a desired pressure, andreleased or stored (e.g., in a separate storage container). In someembodiments, the produced biogas may include different elements orcompounds as produced by different microorganisms or by the digestion ofdifferent VOCs or other materials. According to one embodiment, forinstance, two or more gasses (e.g., methane and carbon dioxide) may beproduced in different relative proportions by weight and/or volume(e.g., 80/20, 70/30, 60/40, etc) although the compounds may also beproduced in relatively equal proportions.

According to various embodiments, metabolism of VOCs and/or productionof biogas may slow, even in embodiments in which the temperature ismaintained at desired levels. In such cases, the bioreactor system 400may receive a catalyst or other elements to enhance or boosteffectiveness. As an example, additional microorganisms may beintroduced into the bioreactor reservoir 404 (e.g., prior to or duringfeeding in additional wastewater from the feed reservoir 402). Inaddition or as an alternative, VOCs or materials that can be metabolizedand digested by the anaerobic microorganisms may be added. For instance,where methanol is metabolized by the anaerobic microorganisms, aquantity of methanol may be added to the bioreactor reservoir 404 (e.g.,prior to or during feeding of wastewater from the feed reservoir 402) tostabilize the conditions in the bioreactor reservoir 404 and/or improveactivity of the anaerobic microorganisms.

Although the foregoing description contains many specifics, these shouldnot be construed as limiting the scopes of the inventions recited by anyof the appended claims, but merely as providing information pertinent tosome specific embodiments that may fall within the scopes of theappended claims Features from different embodiments may be employed incombination. In addition, other embodiments of the invention may alsolie within the scopes of the appended claims All additions to, deletionsfrom and modifications of the disclosed subject matter that fall withinthe scopes of the claims are to be embraced by the claims

What is claimed:
 1. A wastewater treatment facility, comprising: a feedreservoir containing wastewater; a bioreactor reservoir positioned toreceive the wastewater from the feed reservoir and to remove organiccompounds from the wastewater; and a valving station between the feedreservoir and the bioreactor reservoir, the valving station comprising:one or more pumps; a wastewater conditioning element; and one or morevalves for using the one or more pumps to selectively pass to thewastewater conditioning element wastewater from the feed reservoir orwastewater re-circulated in the bioreactor reservoir.
 2. The wastewatertreatment facility of claim 1, wherein the valving station is positionedbetween a wastewater outlet of the feed reservoir and a wastewater inletof the bioreactor reservoir.
 3. The wastewater treatment facility ofclaim 1, wherein the valving station is positioned between a wastewateroutlet of the bioreactor reservoir and a wastewater inlet of thebioreactor reservoir.
 4. The wastewater treatment facility of claim 1,wherein the one or more pumps includes at least two pumps.
 5. Thewastewater treatment facility of claim 4, wherein: a first pump isconnected to the feed reservoir and the bioreactor reservoir fortransferring wastewater from the feed reservoir to the bioreactorreservoir; and a second pump is connected to the bioreactor reservoirfor re-circulating wastewater in the bioreactor reservoir.
 6. Thewastewater treatment facility of claim 1, wherein a first pump of theone or more pumps is connected to an outlet of the feed reservoir and toan outlet of the bioreactor, and wherein the one or more valves areconfigured to selectively use the first pump to transfer wastewater fromthe feed reservoir to the bioreactor reservoir and to re-circulatewastewater in the bioreactor reservoir.
 7. The wastewater treatmentfacility of claim 1, wherein a first pump of the one or more pumps isconnected to two outlets of the bioreactor reservoir, the two outletscorresponding to a wastewater outlet and a solid materials outlet. 8.The wastewater treatment facility of claim 1, wherein the wastewaterconditioning element is a heater.
 9. The wastewater treatment facilityof claim 1, wherein the one or more valves are configured to allowwastewater from the feed reservoir or re-circulated wastewater in thebioreactor reservoir to selectively bypass the wastewater conditioningelement.
 10. The wastewater treatment facility of claim 1, wherein thefeed reservoir is a moveable tank.
 11. The wastewater treatment facilityof claim 1, wherein the feed reservoir is a skim pond.
 12. Thewastewater treatment facility of claim 11, further comprising one ormore evaporation ponds downstream from the bioreactor reservoir.
 13. Thewater treatment facility of claim 1, wherein the valving stationincludes one or more sampling lines, the one or more sampling linesincluding: a sampling line for sampling output of the wastewaterconditioning element; a sampling line for sampling output of the feedreservoir which bypasses the wastewater conditioning element; or asampling line for sampling re-circulated wastewater of the bioreactorreservoir which bypasses the wastewater conditioning element.
 14. Amethod for treating wastewater and maintaining the wastewater at adesired temperature, comprising: accessing untreated wastewater from afeed reservoir; transferring the wastewater from the feed reservoir to abioreactor reservoir for mixing with treated wastewater and anaerobicmicroorganisms in the treated wastewater; conditioning one or more ofthe untreated and treated wastewater such that: when the untreatedwastewater is being conditioned, the untreated wastewater is selectivelytransferred to a conditioning element after being output from the feedreservoir and prior to being input to the bioreactor reservoir; and whenthe treated wastewater is being conditioned, the treated wastewater isre-circulated and selectively transferred to the conditioning elementand thereafter re-input into the bioreactor reservoir; and treating theuntreated wastewater with the anaerobic microorganisms to reduce acontent of volatile organic compounds dissolved in the untreatedwastewater.
 15. The method of claim 14, wherein conditioning one or moreof the untreated and treated wastewater includes using a heater as theconditioning element.
 16. The method of claim 14, wherein conditioningone or more of the untreated and treated wastewater includes using oneor more valves for selectively conditioning the untreated and treatedwastewater using the same conditioning element.
 17. The method of claim14, further comprising: transporting the untreated wastewater to awastewater treatment site where the feed reservoir is located oraccessed.
 18. The method of claim 14, further comprising: addinganaerobic microorganisms to the bioreactor reservoir.
 19. The method ofclaim 14, further comprising: adding organic materials to the treatedwastewater, the organic materials being digestible by the anaerobicmicroorganisms.
 20. The method of claim 19, the added organic materialsincluding methanol.
 21. The method of claim 14, further comprising:releasing gas from the bioreactor reservoir, the released gas includinggas generated by the anaerobic microorganisms metabolizing the volatileorganic compounds.
 22. The method of claim 21, wherein releasing gasfrom the bioreactor reservoir includes collecting the gas in a storagecontainer.
 23. A wastewater treatment facility, comprising: a feedreservoir having a fluid outlet; a bioreactor reservoir downstream fromthe feed reservoir, the bioreactor reservoir including at least oneinput, a fluid output, and a solid materials output; and a valvingstation downstream from the feed reservoir and upstream from thebioreactor reservoir, the valving station including: a first pressureelement for receiving fluid from the fluid outlet of the feed reservoirand transferring the fluid output to the at least one input of thebioreactor reservoir; a second pressure element for receiving fluid fromthe fluid and solid materials outlets of the bioreactor reservoir andre-introducing the fluid and solid materials to the bioreactor reservoirthrough the at least one input of the bioreactor reservoir; a heaterdownstream relative to the first and second pressure elements andupstream relative to the input of the bioreactor reservoir; and one ormore valves for selecting whether output of the first and secondpressure elements is delivered to, or bypasses, the heater.
 24. Thewastewater treatment facility of claim 23, wherein the first and secondpressure elements include a gravity feed or a pump.
 25. The wastewatertreatment facility of claim 23, wherein the first pressure element is apump configured to selectively receive fluid from each of the feedreservoir and the bioreactor reservoir, while the second pressureelement is a pump configured to selectively receive fluid and solidmaterials from the bioreactor reservoir but not the feed reservoir.